Internal Speaker; Ihf - Nokia NPL-4 Series Manual

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Internal speaker

There is a dynamic earpiece with impedance of 32 ohms. The earpiece is low impedance
one since the sound pressure is to be generated using current and not voltage as the
supply voltage is restricted to 2.7V. The earpiece is driven directly by the UEMEK and the
earpiece driver (EARP & EARN outputs) is a fully differential bridge amplifier with 6 dB
gain.
UEMEk
EARP
EARN

IHF

The NPL-4/5 uses the D-class amplifier to gain signal to IHF speaker. The integrated
Hands Free Speaker is used to generate polyphonic ringing tones, FM radio, PoC and IHF
audios. Speaker capsule is mounted under the antenna. Spring contacts are used to con-
nect the IHF Speaker contacts to the system PWB.
Class-D amplifier, it produces high efficiency, which leads to the lower current consump-
tion and makes the thermal issues negligible as well compared to the traditional solu-
tions.
UEMEk
UPP
Copyright © 2005 Nokia Corporation. All rights reserved.
Issue 2 05/05
Figure 34: IEarpiece Connection
27pF
Figure 35: IHF Connection
VBatt
1u
10n
PAOUTP IN+
PAOUTN IN-
10n SHUTDOWN
GenIO(14)
System Module and User Interface
1000Ω@100MHz
14V 14V
27pF
100n
220ohm/100MHz
V01
LM4667
V02
GAINSEL
NPL-4/5/
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